A pictorial review of lung torsion using 3D CT cinematic rendering

Comparison of two 3D reconstruction models for understanding of complicated female pelvic tumors

OBJECTIVE

Three-dimensional (3D) reconstructed models have been shown to improve visualization in complex female pelvic tumors. Cinematic rendering (CR) is a 3D imaging technique for computed tomography (CT) images, which creates more realistic images with the ability to enhance imaging of anatomical features for diagnosis. This study was set up to compare two types of 3D models and to validate the use of 3D anatomical techniques for the diagnosis of complex female pelvic tumors.

METHODS

The preclinical, randomized, two-sequence crossover investigation was performed from December 2022 to January 2023 at First Affiliated Hospital of Chongqing Medical University. Sixteen residents and 10 attending surgeons assessed the cases of 23 patients with two types of 3D model images. The surgeons were randomly assigned to two assessment sequences (CR-3D model group and CT-3D model group). For each case, participants selected one question that probed fundamental questions about the tumor's genesis throughout each assessment period. Following a 4-week washout period, case assessments were transferred to the other image modality.

RESULTS

The main result assessment was the accuracy of the answers. The time to answer the questions and the case assessment questionnaire was added as a secondary outcome. The mean scores in the CR-3D models (19.35 ± 1.87) varied significantly from those in the CT-CR group (16.77 ± 1.8) (P < 0.001), and solving the questions in the CT-3D model sequence (41.96 ± 6.31 s) varied significantly from that in the CR-3D model sequence (52.88 ± 5.95 s) (P < 0.001). Subgroup analysis revealed that there were statistically significant variations in the scores of female reproductive tumors, pelvic tumors other than the reproductive system, and retroperitoneal tumors (P = 0.005). Analysis of the assessment questionnaire showed that more surgeons choose CR 3D reconstruction (8.31 ± 0.76 vs 7.15 ± 1.19, P < 0.001).

CONCLUSIONS

The results suggest that each 3D reconstruction method has its own advantages. Surgeons feel that CR reconstruction models are a useful technique that can improve their comprehension of complex pelvic tumors, while traditional 3D models have an advantage in terms of speed to diagnosis.

Imaging Features of Uncommon Entities That Manifest with Torsion

Torsion is the twisting of an object along the axis, and various structures (organs and tumors) in the body can twist. Torsion causes initial lymphatic and venous outflow obstruction, leading to congestive edema, enlargement, venous hemorrhagic infarction, and surrounding edema. It can also cause subsequent arterial obstruction depending on the degree of torsion, leading to ischemia, infarction, necrosis, gangrene, and surrounding inflammation. Therefore, in several cases of torsion, immediate surgical intervention is required to improve blood flow and prevent serious complications. Clinical manifestations of torsion are often nonspecific and can affect individuals of varying ages and sex. Imaging plays an important role in the early diagnosis and management of torsion. Multiple imaging modalities, including US, radiography, CT, and MRI, are used to evaluate torsion, and each modality has its specific characteristics. The imaging findings reflect the pathophysiologic mechanism: a twisted pedicle (whirlpool sign), enlargement of the torsed structures, reduced blood flow, internal heterogeneity, and surrounding reactive changes. The whirlpool sign is a definitive characteristic of torsion. In some cases, despite poor internal enhancement, capsular enhancement is observed on contrast-enhanced CT and MR images and is considered to be associated with preserved capsular arterial flow or capsular neovascularization due to inflammation. Radiologists should be familiar with the pathophysiologic mechanisms, clinical characteristics, and imaging characteristics of torsion in various structures in the body. Since other articles about common organ torsions already exist, the authors of this article focus on the uncommon entities that manifest with torsion. ©RSNA, 2024.

3D Visual Guide to Lines and Stripes in Chest Radiography

Chest radiography continues to be the first-line imaging modality for evaluation of the chest. Interpretation is based on the understanding of complex three-dimensional (3D) structural relationships, which are translated into a two-dimensional (2D) plane. These 2D projections form multiple "lines and stripes" on chest radiographs, representing the interfaces between the pulmonary parenchyma, pleura, and normal mediastinal structures. Given the subtlety of overlying tissue and the need to mentally synthesize planar images into three dimensions, structural relationships may be difficult to appreciate. An understanding of these relationships forms the basis of recognizing pathologic conditions and providing an accurate differential diagnosis, which can assist in targeted appropriate further workup. On a 2D radiograph, this means recognizing the normal lines and stripes as well as their appearance when effaced or displaced. Once this abnormality is identified, a focused differential diagnosis can be generated, which can be further narrowed on the basis of other factors, such as patient history or ancillary findings. Three-dimensional cinematic rendering is an innovative tool that can help radiologists grasp these anatomic relationships and discern subtle findings at radiography. This technique allows improved visualization of structures such as the pleura that are difficult to appreciate with traditional imaging modalities. The authors provide an updated review of lines and stripes on chest radiographs, using 3D cinematic rendering as a teaching tool. ©RSNA, 2023 Quiz questions for this article are available in the supplemental material.

Segmental Lung Torsion

The authors report an unusual case of segmental lung torsion detected at CT pulmonary angiography in a patient with dyspnea. This case highlights the importance for clinicians and radiologists to consider and be familiar with the diagnosis of lung torsion, a rare and potentially life-threatening pathologic condition that can be successfully treated with emergent surgery if detected early. Keywords: CT, CT Angiography, Pulmonary, Thorax, Lung, Emergency Radiology Supplemental material is available for this article. © RSNA, 2023.

Photorealistic Depiction of Intracranial Tumors Using Cinematic Rendering of Volumetric 3T MRI Data

RATIONALE AND OBJECTIVES

Cinematic Rendering (CR) incorporates a complex lightning model that creates photorealistic models from isotropic 3D imaging data. The utility of CR in depicting volumetric MRI data for pre-therapeutic planning is discussed, with intracranial tumors as a demonstrative example.

MATERIALS AND METHODS

We present a series of Cinematically Rendered intracranial tumors and discuss their utility in multidisciplinary pre-therapeutic evaluation. Isotropic, high-resolution, volumetric MRI data was collected, and CR was performed utilizing a proprietary application, "Anatomy Education" Siemens, Munich, Germany.

RESULTS

Discrimination of cortex to white matter, brain surface to vessels, subarachnoid space to cortex and skull to intracranial structures was achieved and optimized by using various display settings on the Anatomy education application. Progressive removal of tissue layers allowed for a comprehensive assessment of the entire region of interest. Complex, small structures were demonstrated in very high detail. The depth and architecture of the sulci was appreciated in a format that more closely mimicked gross pathology than traditional imaging modalities. With appropriate display settings, the relationship of the cortical surface to the adjacent vasculature was also delineated.

CONCLUSION

CR depicts the anatomic location of brain tumors in a format that depicts the relative proximity of adjacent structures in all dimensions and degrees of freedom. This allows for better conceptualization of the pathology and greater ease of communication between radiologists and other clinical teams, especially in the context of pretherapeutic planning.

Virtual or real: lifelike cinematic rendering of adrenal tumors

The adrenal gland is small in size and hidden in location. Adrenal tumors are relatively difficult to diagnose due to the wide variety of tumors and partial overlap of image features. Cinematic rendering (CR) is a novel, three-dimensional post-processing technology that simulates how light propagates in the real world, providing high-resolution visualizations that truly present subtle anatomical details. We retrospectively collected a series of pathologically confirmed adrenal tumor cases, raw data was introduced into the post-processing workstation, and different tools and templates of CR software were used for reconstruction and rendering. Compared with traditional black and white two-dimensional images and three-dimensional volume rendering (VR) images, CR images were more colorful, layered, and closer to the truth. CR has potential in diagnosing and preoperative planning of adrenal tumors, allowing vivid and realistic visualization of tumor location, morphology, different components (solid, cystic, fat, calcification, etc.), the pattern of enhancement, and the relationship with surrounding tissues and organs.